[gradsusr] convert world coordinate distance to real distance (km)

wendi harjupa wendiharjupa at gmail.com
Tue Nov 8 19:55:48 EST 2016

```Dear Mr. Phil

I am very sorry, I was mistake to send you the coordinate, and I also did
mistake in my calculation. I put wrong number. Now, I can get good result.

Thank you very much for your fully assistance.

Best regards,
wendi

On Wed, Nov 9, 2016 at 12:43 AM, HARVEY, PHILIP O NH-03 USAF AFMC 412
OSS/OSW <philip.harvey.1 at us.af.mil> wrote:

> Hello Wendi,
>
> that your 2 coordinates were 34.5 lat 135 lon and 35 lat 135.5 lon.  That
> means the 2 points are a little more than 0.5 degrees apart.  The distance
> between 2 latitude parallels is 60 NM (111.12 KM) and half of that would be
> 30 NM (55.56 KM) so the computation for those 2 coordinates is correct and
> cannot be 5 KM.  If those 2 coordinate pairs are correct, your estimate is
> wrong by a factor of 10.  I entered the 2 coordinates above into the online
> distance calculator at http://www.csgnetwork.com/gpsdistcalc.html and the
> results match the formula.
>
> Phil
>
> ------------------------------------------------------------
> ----------------------------
> PHILIP O. HARVEY, NH-III, DAF
> Flight Chief/Staff Meteorologist/COR/CL
> 412 OSS/OSW
> 235 S. Flightline Rd.
> Edwards AFB, CA  93524-6460
>
> Phone:  (661) 277-4507,  DSN:  527-4507
>   Fax:  (661) 277-9607,  DSN:  527-9607
> Total: (1322) 555-4114,  DSN: 1055-4114
>
> -----Original Message-----
> On Behalf Of wendi harjupa
> Sent: Monday, November 07, 2016 4:42 PM
> Subject: Re: [gradsusr] convert world coordinate distance to real distance
> (km)
>
> Dear Mr Phil
>
> Thank you very much for your explanation.
> But the result is totally wrong.
> The estimate result just about 5 km.
>
> I think I need the formula for short distance, which is we have to
> consider the earth is flat.
>
> Best regards,
> wendi
>
> On Tue, Nov 8, 2016 at 1:24 AM, HARVEY, PHILIP O NH-03 USAF AFMC 412
> OSS/OSW <philip.harvey.1 at us.af.mil <mailto:philip.harvey.1 at us.af.mil> >
> wrote:
>
>
>         Wendi,
>
>         The formula expects input in radians.  You must first convert the
> input latitudes and longitudes from degrees to radians.  For example, 34.5
> * PI / 180 = 0.011294, etc.  Then apply the formula using your example
> values.  The result of the formula using 34.5 lat 135 lon and 35 lat 135.5
> lon is 38.8276 nautical miles or 38.8276 NM * 1.852 = 71.90872 KM.
>
>         Phil
>
>
>
>         -----Original Message-----
>         Sent: Saturday, November 05, 2016 7:34 AM
>         Subject: Re: [gradsusr] convert world coordinate distance to real
> distance (km)
>
>         Wendi,
>         Keep in mind what happens when you alter the geographical bounds
> in the control file. Those XDEF/YDEF/ZDEF/TDEF lines control the bounds of
> your dimension environment when running grads. Now that you've set the xdef
> and ydef to start at 1 and increment by very small values, the maximum x
> and y values in your dimension environment are now
>
>
>         max_x = 1 + 319*0.005483962 = 2.749
>
>         max_y = 1 + 319*0.00452226 = 2.443
>
>
>         Notice how this math is derived from your control file. This means
> the maximum values for lat and lon that won't result in an error are 2.749
> and 2.443. You set lat and lon to well outside those ranges in your script,
> which is why you are getting the error. You can instead reset lat and lon
> so that they're within the bounds above, but I think that's getting away
> from the problem you're trying to solve. My understanding is that you want
> to plot a field using linear distance coordinates rather than geographical
> coordinates. If so, then you don't want to be using lat/lon to set your
> dimensions. Use 'set x' and 'set y', and also set your initial value in
> your XDEF and YDEF lines to zero so that the lower left corner of your
> plots will be at distance coordinate (0,0) and increasing as you go up and
> right. Is this what you wanted to do?
>
>
>         Jeff Duda
>
>
>         On Sat, Nov 5, 2016 at 1:35 AM, wendi harjupa <
> wendiharjupa at gmail.com <mailto:wendiharjupa at gmail.com>  <mailto:
> wendiharjupa at gmail.com <mailto:wendiharjupa at gmail.com> > > wrote:
>
>
>                 Dear Mr. Jeff
>
>                 I have tried it for several times, but it does not work.
>                 I am very sorry for asking you again.
>
>                 I got an error as below
>                 Data Request Warning:  Request is completely outside file
> limits
>                 Cannot contour grid - all undefined values
>                 Error in xcbar.gs <http://xcbar.gs>  <http://xcbar.gs> :
>
>
>                 Here my ctl file and gs file
>
>                 try.ctl
>
> 1700/data/KINKI00001-20150808-1400-G000-EL000000.bin
>                 UNDEF -999
>                   XDEF 319 LINEAR 1 0.005483962
>                   YDEF 319 LINEAR  1 0.00452226
>                 #  ZDEF  81 LINEAR 125 250
>                 TDEF   120 LINEAR 09:00Z14JUL1500 60yr
>                 VARS   1
>                 rr    81 99 rainfall (mm)
>                 ENDVARS
>
>
>                 try.gs <http://try.gs>  <http://try.gs>
>
>                   'reinit'
>                    'open /TAKAYASU/wendi/overlay_cappi/try.ctl'
>                    'setXrain.gs'
>                 #   'set mproj off'
>                 #   'setCOMMON.gs'
>                    'set lon 134.9 135.4'
>                    'set lat 34 34.5'
>                    'd  rr'
>                    'xcbar  8.6 8.8 0.8 4 -fw 0.11 -fh 0.15 -edge triangle
> -fstep 1 -line on -lc 1'
>                    'set strsiz 0.15 0.15'
>                    'draw string 8.5 4.15 mm'
>
>                 #   'set xaxis 0 10 1'
>                 #   'set yaxis 0 10 1'
>
>                    'close 1'
>
>                 Thank you very much.
>                 Best regards,
>                 wendi
>
>
>
>
>
>
>
>                 On Thu, Nov 3, 2016 at 1:37 AM, Jeff Duda <
> jeffduda319 at gmail.com <mailto:jeffduda319 at gmail.com>  <mailto:
> jeffduda319 at gmail.com <mailto:jeffduda319 at gmail.com> > > wrote:
>
>
>                         Wendi,
>
>                         You can always change the text of any control
> file. There should not be anything stopping you from doing that. Please
> clarify what you mean.
>
>
>                         Jeff
>
>
>                         On Tue, Nov 1, 2016 at 11:53 PM, wendi harjupa <
> wendiharjupa at gmail.com <mailto:wendiharjupa at gmail.com>  <mailto:
> wendiharjupa at gmail.com <mailto:wendiharjupa at gmail.com> > > wrote:
>
>
>                                 Dear Mr Jeff
>
>                                 Thank you very much for your help.
>
>                                 I have two different types of data set and
> I need to make composite data with those data.
>                                 One data is mismatch, then I need to know
> how far the mismatch.
>
>                                 One of my data set is binary and another
> one is netCDF.
>
>                                 I can change my control file in my binary
> data. But, I cannot do this for my netCDF data.
>                                 Would you mind to suggest me, how to
> change XDEF and YDEF in netCDF data?
>
>                                 Thank you very much
>
>                                 best regards,
>                                 wendi
>
>                                 On Wed, Nov 2, 2016 at 12:02 AM, Jeff Duda
> <jeffduda319 at gmail.com <mailto:jeffduda319 at gmail.com>  <mailto:
> jeffduda319 at gmail.com <mailto:jeffduda319 at gmail.com> > > wrote:
>
>
>                                         Wendi,
>
>                                         It sounds like you want to draw a
> plot with geographic coordinates replaced by straight-line/distance
> coordinates instead. If that is the case, one thing you can try is removing
> the PDEF line from your control file and resetting your XDEF and YDEF lines
> to start at 0 (but keep the delta value). That might work. If that doesn't
> work, you could also try turning off the map projection in grads (set mproj
> off) and then using 'set xaxis' and 'set yaxis' in clever ways to make it
> look like the map you draw is in terms of linear distance. Good luck.
>
>
>                                         Jeff Duda
>
>
>                                         On Tue, Nov 1, 2016 at 9:32 AM,
> HARVEY, PHILIP O NH-03 USAF AFMC 412 OSS/OSW <philip.harvey.1 at us.af.mil
> <mailto:philip.harvey.1 at us.af.mil>  <mailto:philip.harvey.1 at us.af.mil
> <mailto:philip.harvey.1 at us.af.mil> > > wrote:
>
>
>                                                 See Ed Williams' Aviation
> Formulary at http://williams.best.vwh.net/avform.htm <
> http://williams.best.vwh.net/avform.htm>  <http://williams.best.vwh.net/
> avform.htm <http://williams.best.vwh.net/avform.htm> >  for great circle
> distance, etc formulas.  The formula you desire is only requires 1 line and
> can easily be written into a function.
>
>                                                 Phil
>
>
>
>                                                 -----Original Message-----
>                                                 From:
>                                                 Sent: Tuesday, November
> 01, 2016 2:01 AM
>                                                 To: GrADS Users Forum <
> convert world coordinate distance to real distance (km)
>
>                                                 Dear every one
>
>                                                 I have problem with
> converting distance in world coordinate to distance,
>
>                                                 I have map with
>                                                 lon = 135  135.5
>                                                 lat = 34.5   35
>
>                                                 I want to set lon =135, as
> 0 km, and lat=34.5 as 0 km.
>                                                 as we know that 1 deg is
>
>                                                 Is there any function in
> grads that can directly convert the world coordinat distance to real
> distance (km)?
>
>                                                 Please, any help would be
> very appreciate.
>
>                                                 thank you
>                                                 regards,
>                                                 wendi
>
>
>
> _______________________________________________
>
>
>
>
>
>
>
>                                         --
>
>                                         Jeff Duda
>                                         Post-doctoral research associate
>                                         University of Oklahoma School of
> Meteorology
>
>
>                                         ______________________________
> _________________
>
>
>
>
>
>                                 ______________________________
> _________________
>
>
>
>
>
>
>                         --
>
>                         Jeff Duda
>                         Post-doctoral research associate
>                         University of Oklahoma School of Meteorology
>
>
>
>                         _______________________________________________
>
>
>
>
>
>                 _______________________________________________
>
>
>
>
>
>
>
>         --
>
>         Jeff Duda
>         Post-doctoral research associate
>         University of Oklahoma School of Meteorology
>
>
>         _______________________________________________
>
>
>
>
> _______________________________________________